Flashcards in Digestion Deck (72):
The six basic nutrients are
Macro vs micro nutrients
Macro: Carbohydrates, fats, protein. Large quantities needed by mass
Micro:Vitamins and minerals. Small amounts by mass
Distribution of nutrients male vs female
Water 60% 50%
Protein 20% 18%
Fat 18% 30%
Carbs 2% 2%
Word carbohydrate comes from
Hydrate: Water is made of 2 hydrogen, one oxygen. All carbohydrates contain these elements in that ratio
Exist in ratio of one carbon to two hydrogen to one oxygen
What are carbohydrates?
Energy molecules, either sugars or starch
What is starch?
100s of glucose molecules joined together by covalent bonds. Does not taste sweet. Aka amylose (plant)
Glycogen is animal starch. Polysaccharide.
How organisms store glucose. Is insoluble. More branches, less soluble (glycogen)
How does starch begin digestion?
Broken down in mouth by enzyme called salivary amylase. Starch ---Salivary amylase, H2O----> Maltose + energy
What is the formula for glucose, galactose, and fructose?
What is the formula/makeup of maltose, lactose, and sucrose?
What is a disaccharide and how are they formed?
Two monosaccharides bonded through dehydration synthesis
G+G --enzyme-->H20 + G-G (Held together with peptide bond)
How are disaccharides converted to monosaccharides?
G-G + H2O --Maltase(etc)--> G + G
How are sugars transported?
They are dissolved in water. They are converted into a transport form that makes them less likely to be metabolized. Usually made into disaccharide.
What is cellulose?
An insoluble starch found widely in plants and it is needed for support and structure of the cell walls. It is the most widely used structural organic material on earth. The bonds between the glucose molecules are more resistant to hydrolysis than starch. Cellulose is digested by enzymes called cellulases. The enzymes are produced by protozoans, invertebrates in the digestive tract. Cannot be digested by humans.
Fats and energy
Fats are composed of the same atoms as carbohydrates but in a different arrangement.
Fats provide 2x as much energy per gram than either carbohydrates or proteins
Fats can be formed when the body converts excess energy from carbohydrates or proteins into fat in the liver
Important functions of fats
-source of energy
-to dissolve fat soluble vitamins
-fat under our skin, subcutaneous fat, helps insulate
-deep internal fat cushions and protects organs
Adverse effects of fat
-excess leads to obesity
-obesity places strain on the heart, muscles, and other body systems
Structure of fats
Fatty acid: Mono, Di, or Triglyceride
Saturated vs. Unsaturated fats
-solid at room temp
-max amount of hydrogen bonded to carbon
-higher melting point
Ex. Steric acid
-liquid at room temp
-Fewer hydrogen atoms bonded to carbon, double bonds present
-lower melting point
-double bonds cause bends in molecule
Trans: Unsat with qualities of Sat. Hydrogens on opposite sides creating linear molecule
-white waxy substance
-produced by liver, transported by bloodstream
-high blood cholesterol levels are linked to increase risk of heart disease
-can cling to walls of blood vessels and reduce blood flow (arteriosclerosis) Can lead to heart attack
-found in animal products
-polyunsaturated fats tend to lower blood cholesterol levels. Saturated tend to increase blood cholesterol levels
Functions of proteins
-building, repair, maintenance of tissue especially during growth spurts during first two years after birth and during adolescence
-form a major part of muscles, internal organs, the brain, nerves and skin
-play important role in fluid balance
-needed to make enzymes, antibodies, and hormones
-maintain pH balance
Structure of protiens
-100s to 1000s of amino acids
-amino acids are composed of carbon, hydrogen, oxygen, nitrogen, and occasionally sulfur
-20 different kinds
-the order and number of amino acids determine the type of protein
Essential vs. nonessential amino acids
Essential: Cannot be synthesized and must be included in diet. 8. Lack of any can block production of proteins. Proteins that contain all the essential amino acids are known as complete proteins. Proteins that are lacking are called incomplete. Incomplete that can be matched to obtain all the essentials are called complementary
Non: Can be synthesized from carbohydrates, fats, and amino acids
Proteins as an energy source
-proteins are not stored like carbohydrates or fats for later use
-if body requires amino acids which are not available in diet tissue proteins are broken down. Extra amino acids are used as energy or lost.
-if amount available is greater than amount needed converted into glucose and then fat. During the conversion process the nitrogen is removed and excreted in urine. The body cannot convert fats to protein because of this.
Sources of protein:
-plants and vegetables, although usually incomplete
Functions of vitamins
-help control chemical reaction in the body
-can be used over and over without being used up but do eventually need to be replaced
Types of vitamins
Water soluble: Vitamin B (some), C
Fat soluble: Vitamin D, E, A, K
Fat must be present int the digestive tract in order for these vitamins to be absorbed. Should be taken with a meal.
Sources of vitamins and what decreases vitamin content?
-well balanced diet usually has everything you need
Can be decreased by:
-type of soil
-transportation: Vitamin content reduced by heat, light, and oxygen
-harvesting crops before they are ripe
-freezing or storing
-cooking or canning
-body can produce vitamin D when skin exposed to ultraviolet light. Vitamin K and some B are produced by bacteria in the large intestine
Function/structure of minerals?
-inorganic elements that do not need to be digested before absorption
-help control water balance
-control acid base balance
-important part of enzymes and hormones
-structural part of bone and cartilage
-assist enzymes in many chemical reactions
Types of minerals and examples
Large amounts: Fe, Ca, P, K, Na, F, Cl
Trace minerals (many in small quantities, minimal effect)
Heavy metals: Au, Ag, Zn, Mg.
Sources of minerals:
-Vegetables, fruits, meats, eggs, milk, cereals and water. Liver is a good source of iron.
Functions of water
-dilutes and helps dispose of the body wastes and toxins
-bathes every cell which enables dissolved nutrients and wastes to pass in and out
-needed to transport the nutrients, wastes and blood cells along in the bloodstream
Sources of water: Also output
-Food (Fruits and vegetables are mainly water)
-the percentage of water in the human body decreases as get older
Output: Sweating, breathing, urination, defecation
Draw and label the digestive system
What are the stages of digestion?
Ingestion, digestion (physical and chemical), apsorption, egestion
What is mechanical digestion?
Large food particle--Chewing/grinding--> Small food particles
Mechanical digestion increases surface areas for enzymes
How in general do enzymes work? (Digestion)
-there are specific enzymes for specific molecules
-molecule being acted on is called the substrate
-the substrate and enzyme must have complementary size and shape
-can only work on one substrate molecule at a time so they work fast and can be recycled
-influenced by temperature and pH
-work by inserting water into substrate to be broken down
-names of enzymes end in "ase"
Draw and label the mouth
How does physical digestion happen in the mouth?
-water dissolves nutrients
-relax jaw muscles, tongue contracts to move food between teeth, contract jaw muscles
-tongue pushes food upwards against the ridged hard palate to separate food
What are the components of saliva and how they work?
2. Mucus (Moistens and forms food bolus, lubrication)
Amalose+h20--Salivary amylase-->Maltose+Unfinished amalose
Maltose+h2o--salivary maltase-->2 Glucose
What are functions of the tongue and how do you determine what goes in your mouth?
-pushes food against soft palate to form bolus
-assists in swallowing
-determines what you eat
-sweet, sour, bitter, salty,
Label a tooth
What is the function of the soft palate and uvula?
Pushed up by food when swallowing and closes over the nasal cavity.
What is peristalsis and what happens? (Draw it maybe)
A wave like series of contractions by which food moves through your digestive system
Contraction of longitudinal muscle ahead of food bolus increases tension and opens lumen.
Contraction of circular muscles behind food bolus pushes it forward.
Draw a cross section of the esophagus. Structure?
Connective tissue, longitudinal muscle, circular muscle, (blood vessels, lymphatic vessels, nerves,) Submucosal layer, mucosal layer (epithelial cells + mucus)
25 cm long
2.5 cm wide
Structure/ conditions of stomach?
Same as esophagus but with extra oblique muscle under circular muscle tissue and thin muscle layer under mucosal.Thicker mucosal layer. Mucus secreting cells, oxyntic/parietal cells secrete HCl, Chief zymogen cells secrete pepsinogen, zymogen cells secrete other enzymes. Ridges of Rugae with lots of gastric pits. Cardiac and pyloric sphincter on ends.
Bolus mixed with juices becomes acidic chyme (ph 2)
What is a hiatus hernea?
The esophagus must travel through the diaphragm. This "space" is the esophageal hiatus. Pressure on diaphragm created by improper breathing during exertion can cause the stomach to start being squeezed up through the hiatus.
What digestion happens in the stomach?
-muscles contract to push bolus against the rugae to split the bolus apart
Protein--HCl-->Polypeptides+H2O--Pepsin-->Peptides (4-12 amino acids long)
Any other proteins including salivary enzymes and pathogens are digested in the same way.
Protein digested for long time, carbohydrates sent through, fats sent through slowly.
How does infant digestion differ in the stomach?
Breast milk consists of peptides and amino acids. Less digestion must take place. pH stomach: 5
Liquid triglycerides--Renin-->Semi-solid triglycerides
SS Triglycerides+H2O--Gastric lipase-->2 fatty acids + Monoglycerides
As carbohydrates, fruits, vegetables, simple proteins are introduced fat digestion is phased out. pH increases
What is the structure of the duodenum?
-ridged but not much absorption
-2.5 cm wide
-25 cm long
-common bile duct and pancreatic duct dump stuff in early on
What chemical reactions (and physical digestion) occur in the duodenum?
Acidic chyme (HCl)+NaHCO3--->NaCl+H2O+CO2(aq)(g)
Blob of triglycerides + bile ---> Tiny droplets of triglycerides called micelles. (Physical digestion, emulsification)
Triglycerides+H2O--Pancreatic lipase-->2 fatty acids + monoglyceride
Phospholipids + H2O--Pancreatic phospholipase-->Phosphate group+Diglyceride
Diglyceride--Lipase-->1 fatty acid + monoglyceride
Maltose+h2O--Pancreatic maltase-->2 glucose
Peptides (4-12 amino acids) + H2O--Pancreatic peptidase-->Smaller peptides and amino acids
Nucleic acids + H2O--Nucleases-->Nucleotides
Nucleotides + H2O --Nucleosidases-->Phosphate group, Nitrogenous base, sugar
What chemical digestion occurs in the jejunum?
Maltose + H2O--Intestinal Maltase-->2 Glucose
Sucrose + H2O--Intestinal Sucrase-->G+F
Tripsinogen + H2O ---Enterokinase--->Trypsin
Small peptides + H2O---Trypsin--->Tripeptides, dipeptides, amino acids
Tripeptides, dipeptides + H2O---Erepsin--->Amino acids
Triglycerides + H2O--Intestinal Lipase--> 2 fatty acids + monoglycerides
(Large monoglycerides + H2O--Intestinal Lipase--> fatty acid + glycerol)
What is the structure of the jejunum and ileum?
Jejunum: 2.5 cm wide and 3 m long
Ileum: 2.5 cm wide 4 m long
Lined with rides covered with villi which are covered in microvilli (cilia). Between villi are crypt of Lieberkuhn which secrete enzymes. Otherwise same structure as esophagus. (See text for pic)
How are nutrients absorbed by villi?
Water soluble enters by diffusion. (All sugars, minerals, vitamins B, C, amino acids, alcohol, other substances)
When concentration of lumen nutrients equals concentration of cells moved by active transport. (Requires some energy)
C6H12O6 cannot diffuse directly, only with the help of protein. FACILITATED DIFFUSION
Not water soluble: Monoglycerides, fatty acids, Vitamins D E A K, Medications surrounded by bile to prevent sticking
Enter epithelial by diffusion and active transport
In cells monoglyceride and 2 fatty acids combines by golgi into triglycerides and surrounded by protein coat and secreted into lacteal.
Other stuff just surrounded and secreted
What is the pathway nutrients follow from the villi and what happens at the liver?
Mesenteric venule-->Mesenteric vein-->Hepatic Portal Vein-->Liver
-Glucose stored, blood sugar kept at 5% assisted by insulin
-takes out alcohol and other toxins. Converts alcohol into fat, sclerosis of the liver
-this requires multiple passes. 1 hour to remove one drink of alcohol
-dumps in UREA from CO2 and ammonia
-->Hepatic vein-->Inferior Vena cava--->Heart--->Lungs---Heart
-->Hepatic Artery (High O2, High nutrients/toxins)--> Liver
-->Renal artery--->Kidneys (urea removed) -->Inferior vena cava
Fat from lacteal-->Lymphatic vessel-->common thoracic duct-->subclavian vein-->superior vena cava-.....->Adipose cells
(Veins carry low O2 high nutrient blood)
(Arteries carry high O2 some nutrient blood)
What happens in the large intestine?
Cellulose, undigested material, unabsorbed material, water ---E Coli bacteria-->Vitamin K + Vitamin B (absorbed) + CH4 (g) + sulfur(g)
Specially designed for H2O absorption. About 90% absorbed. Cellulose holds on to create optimal 60% solid to 40% water ratio of feces.
How long does food spend in each area of the digestive tract?
Mouth: 5-30 s
Stomach: 2-24 hours
Small intestine: 3-4 hours
Large intestine: 18h to 2 days
What is the distribution of body fluids in humans?
Inside cells: 27-30 L
Between cells: 11-13 L
Outside cells: 14-16.5 L
Blood plasma: 3.0-3.5 L
What are key functions of Ca, Fe, Mg, K, Na, Vitamin A, B1, C, D, E?
Ca: forming bone, nerve signals, contracting muscle, clotting blood
Mg: Supporting enzymes, producing protein
K: Conductin nerve signals, contracting muscle
Na: Conducting nerve signals, balancing body fluid
A: Good vision, healthy skin and bones
B1: Metabolizing carbohydrates, growth and muscle tone
C: Healthy bones, teeth, gums, blood vessels, boost immune system
D: Absorbing calcium, forming bone
E: Strengthening red blood cell membranes
What are the roles of water?
Transporting dissolved nutrients into the cells that line the small intestine
-lubricating tissues and joints
-forming essential body fluids such as blood and mucus
-regulating body temperature by sweating
-eliminating waste materials in urine and sweat
What are the four types of feeders?
Filter feeders: Aquatic animals that filter organisms out of the water. Siphons water into its mouth
Substrate feeders: Live on or in their food source and eat their way through it
Fluid feeders: Obtain food by sucking or licking nutrient rich fluids from live plants or animals. Have specially adapted mouth parts
Bulk feeders: Ingest fairly large pieces of food
How does length of the digestive tract vary?
Herbivores have longer digestive tracts and enlarged caecums to help with the digestion of cellulose
Structure of the large intestine and how does peristalsis change in the large intestine?
Periodic contractions, shorter distances. 7.5 cm wide, 1.5 m long
-Too much water
-flushes out good and bad bacteria
-can cause dehydration and death
Treatment: Antibiotics, over the counter meds that slow down peristalsis
Too little fibre--->less H2O retained
-slows down peristalsis, more time for bacteria to do damage
Treatment: Over the counter meds: Speed up peristalsis, fibre supplements
Enema: Add water anally
How does egestion take place?
Some excretion from things that were inside you.
Recutume stores, stretches, nerve impulses, brain.
Brain stimulates peristalsis and relaxation of anal sphincter
This is defecation
Tissues inflamed because acid begins to come in contact and destroy cells. Can happen anywhere in the digestive tract. Usually caused by H. Pylori bacteria which prevent production of mucus.
Inflammatory Bowel disease
Crohn's disease: Anywhere in the alimentary canal (other problems too)
Ulcerative colitis: Attacks the colon
Inflammation of the liver.
A: Contaminated water
B: Sexual contact
Irreversisble replacement of healthy liver tissue with non functioning scar tissue usually caused by alcohol or hepatitis. Few symptoms. Can be detected by blood tests
Cholesterol can precipitate out of the bile and form crystals which grow into gallstones